Hemp sweet home

It wasn’t all that long ago that if you mentioned your joint was made of hemp, you’d have the police scrambling.

But things are clearly changing.

The house could be mistaken for stone, or even an elaborate paint job, but it has, in fact, been made out of industrial hemp.

And the advantages are numerous.

It only took a week to build the walls once the timber frame and roof were constructed.

Hemp builder Shane Hannan, in front of the first house at Shepherds Ground that he has finished with the hempcrete. Picture: Marina Neil

Dungog builder Shane Hannan is building four hemp houses at Shepherds Ground in Butterwick – the first eco village of its kind in NSW where people live in tiny, off-the-grid houses and collectively work the land.

Each hemp wall takes on the triple role of the exterior wall, insulation and the interior gyprock.

If that’s not enough, it’s easy to work with, quickly holds its shape, deters termites, is fire proof and boasts a long list of benefits for those wanting to cut their power bills and escape mould.

Research shows a 20cm hemp wall offers twice as much insulation as a brick home with insulation batts and will never develop mould, Mr Hannah said.

It’s also comes with a price tag that is similar to building a brick home.

“It provides a natural insulating barrier that is a breathable wall and it controls the air quality in the home,” he said.

“The oldest house in the world is in Japan and it’s made out of hemp and lime constructions – that’s about 300 years old,” he said.

“In Britain and France in the last 10 or so years it has really taken off again.”

Shutter boards are used as form work around the timber frame and the hemp, which has been mixed with the Australian Hemp Masonry’s binder, sand and water, is then poured in and compressed.

Mr Hannan said the hemp dried quickly and he could start removing the bottom boards at 1.2 metres.

A 100 square metre home will take six to seven days to finish.

“It comes out like a slightly damp porridge mix,” he said.

“You compress it around the studs to the sides of the shutter boards to form your wall and then build them up.

“Once you take the shutter boards off oxygen starts getting onto it and it starts curing.

“It’s very similar to a brick veneer house going up, the frame holds the house up and the brick goes up as an external skin.”

The curing process takes four to six weeks, depending on the weather.

Then a lime render is put over the outside to help protect it from the elements.

On the inside a natural sealer can be spread over the hemp, if the owners want to feature its golden colour, or a lime or clay render can be used. This variety of hemp does not have THC – a psychotropic cannabinoid which is known for making people high. It is grown and processed locally.

A hemp house built in the Byron Bay area has taken out the 2017 Energy Efficient Building award from the Master Builders NSW.

The hemp construction industry in Australia has been around since the 1990s.

Mr Hannan has been working with hemp for three years.

He trained with Hemp Crete Australia, Australian Hemp Masonry, and went to Wales last year where he trained with one of the big hemp builders in the United Kingdom.

He has already built a few hemp houses in the Dungog area and will start a few more later this year. He expects to build the other 23 tiny houses that have been approved in the later stages of Shepherds Ground over the next few years.

“I can see the potential for it. It provides the sustainability that people have been looking for,” Mr Hannan said. “There’s some good examples of hemp masonry in the UK where the people don’t need any heating or cooling in their house.

“The walls are a really nice golden colour too. You can see the herd that’s gone through and you can pick the different herds that are in it.”

Mr Hannan said building with hemp was also good for the environment.

“As the hemp is growing it’s taking carbon out of the atmosphere,” he said.

“When we put it in the walls with the lime binder we are still taking carbon out of the environment throughout its whole lifestyle.”